Prop for 1963 75hp Evinrude

October 4th, 2017, 04:54 PM

Howdy. I came across the Michigan prop (black) somewhere along the line, but I can't remember where. Anyway, the blade roots are much closer to the centerline of the prop than the other props that I have due to the shape of the prop. What is the difference between these two types of props?

The gearcases on most of the Pre1969 V4s of less than 100hp were a bit of an oddity. The props were actually smaller in Diameter than those used by the 25, 28, 30, 33, 35, and 40hp engines of the day. These engines had very little gear reduction in the gear case, 23:20. There were only 5 propellers offered by OMC for those engines.

10X12 large hub, long drive pin, and large prop nut
10X11 large hub, long drive pin, and large prop nut
10 1/4X10 large hub, long drive pin, and large prop nut
9 1/2X10 large hub, long drive pin, and large prop nut
10X9 1/4 small hub, short drive pin, and small prop nut

Michigan offered those sizes as replacement props and added

10X11 small hub, short drive pin, and small prop nut

On all of the large hub props the short drive pin and the small prop nut could be fitted and used

In later years, OMC only offered the 10X12, the 10X11, and the 10X9 1/4

We had the 10X11, 10X9 1/4 and 9 1/2X10. We used the 10X9 1/4 on our Evinrude Sweet 16 with a 1965 90hp about 98% of the time

Here is a prop chart for an 80hp(a slighty hopped 75) rpms and speeds would still match and the load rating a bit out (click on it, it
gets much bigger)

Comment

With regards to the OMC I/O. They did use this outboard gear case on the 80-90 hp(an 89.5 V4 outboard engine mounted horizontally with a different carb and an oil injection system)and some 110/120hp models. In the case of I/Os, there were a couple more props offered, 10x13 and 10x14

Edit: Also listed for the I/O, from Michigan
10 1/4X9
10 1/2X8
10 3/8X6
All large hub/prop nut